Airlines cancel nearly 1,000 flights Tuesday as disruptions continue to climb

Another 1,000 flights across the U.S. were canceled on Tuesday as disruptions linked to a surge of COVID-19 cases continue to hobble air connectivity networks.

The rise in omicron cases among airline employees, which led to thousands of cancellations over Christmas weekend, was complicated on Monday and Tuesday by severe winter weather in the Pacific Northwest.

Want more airline-specific news? Sign up for TPG's free new biweekly Aviation newsletter.

Of the cancellations, as of 12:30 p.m. ET, 223 were on Skywest, which operates flights as a regional carrier for the major U.S. airlines, including for Delta out of Seattle-Tacoma International Airport. About 9% of SkyWest's flights were canceled, according to flight-tracking service FlightAware.

Alaska Airlines, which operates a hub in Seattle, canceled 84 flights, about 13% of its scheduled operations for the day.

Delta, which also operates a hub in Seattle and was among the airlines most impacted by the rise in COVID cases during Christmas weekend, canceled 94 flights for the day as of Tuesday late-morning, 3% of its schedule. United cut 126, or 5% of its flights, while JetBlue canceled 82 flights — 8% of its schedule.

Although COVID-19-related cancellations had largely affected United, JetBlue and Delta earlier during the holiday period, other U.S. carriers also experienced disruptions as of Tuesday morning.

Allegiant canceled 19 flights — 6% of its schedule — while Spirit canceled 77 flights (9% of its operations). American Airlines cut just 19 flights — less than 1% — while Southwest canceled 82 flights (2% of its schedule).

Regional airlines, meanwhile, continued to share in the mainline carriers' woes. Horizon, which operates flights for Alaska, canceled 26 flights — 12% — while Mesa, which flies for American and United, grounded 30 flights, about 6% of its schedule for the day. Air Wisconsin, which flies for United, cut 22 flights — 9% of its schedule.

The omicron-driven holiday weekend mess was comparable to severe winter storms that have snarled air traffic during past winter travel periods.

In March 2019, for instance, airlines canceled 3,500 flights over three days due to a blizzard. Over the holidays in 2013, almost 10,000 flights were canceled due to winter storms, according to airline analyst Helane Becker of Cowen.

Several airlines have confirmed that a large number of cancellations have been caused by flight crews testing positive for COVID-19 as the omicron variant spreads across the U.S.

"The nationwide spike in Omicron cases this week has had a direct impact on our flight crews and the people who run our operation," a spokesperson for United said on Thursday night. "As a result, we've unfortunately had to cancel some flights and are notifying impacted customers in advance of them coming to the airport. We're sorry for the disruption and are working hard to rebook as many people as possible and get them on their way for the holidays."

The cancellations began rolling in on Thursday afternoon, coming as air travel demand approached pre-pandemic levels.

"We entered the holiday season with the highest staffing levels we've had since the pandemic began and are using all resources available to us to cover our staffing needs," a spokesperson for JetBlue said in a statement this weekend. "Despite our best efforts, we've had to cancel a number of flights, and additional flight cancellations and other delays remain a possibility as we see more Omicron community spread."

Related: Here's what to do if your flight is delayed or canceled

"The health and safety of our crewmembers and customers remains our top priority as we work through this pandemic, and we sincerely apologize for the inconvenience that these schedule changes bring during the holidays," the statement added.

On Monday, the Centers for Disease Control and Prevention (CDC) shortened the time that people who test positive for COVID-19 must isolate, lowering it from ten days to five. The lobbying organization for U.S airlines, Airlines for America, last week asked the CDC to revise the guidance, arguing that the longer period was demonstrably unnecessary and could lead to operational disruptions. Delta and JetBlue also separately made similar requests to the CDC.

"The aviation workforce is essential to maintaining the operations of air travel and cargo supply chains. We appreciate the CDC's announcement today updating isolation guidelines," Airlines for America said in a statement. "The decision is the right one based upon science."

Delta said on Monday night that it was working to implement the new guidelines, suggesting that the shortened isolation period would help it get its operation back on track.

"This is a safe, science-based and more practical approach based on what we now know about the omicron variant," Dr. Henry Ting, Delta's chief health officer, said in a statement. "This new variant has quickly replaced B.1.617.2 as the dominant variant in the U.S. We're learning that while omicron is highly contagious, [it] also involves a shorter duration of illness and a shorter contagious period compared to previous strains."

The cancellations also come after United CEO Scott Kirby sent a letter to customers in November noting that the airline had avoided the types of staffing-related operational issues that have affected other carriers, including Southwest and American. "Yes, you can book with confidence on United," Kirby wrote in the letter.